Risk perception of non-communicable diseases: A systematic review on its assessment and associated factors

Background The burden of non-communicable diseases (NCDs) is increasing. Risk perception of NCDs is an important factor towards the uptake of preventive health interventions. There are various questionnaires assessing risk perception of NCDs, but no internationally standardized questionnaire has been available. Identification of factors associated with risk perception of NCDs may facilitate the development of targeted interventions. This systematic review aims to identify available questionnaire assessing risk perception of NCDs and the factors associated with risk perception of NCDs. Methods The reporting of this systematic review is in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We carried out a literature search through three databases (Scopus, PubMed, Web of Science) and targeted original article published in English between 2012 and 2021. Quality appraisal of the eligible articles was conducted using the Mixed Methods Appraisal Tool. Findings were synthesized using content analysis. Results A total of 86 studies were included. We found a variety of questionnaires assessing risk perception of NCDs, with many differences in their development, domains, items and validity. We also identified several personal, sociopsychological and structural factors associated with risk perception of NCDs. Limitations Most of the included studies were of cross-sectional design, and therefore the quality of evidence was considered low and exhibit a high risk of bias. The role of publication bias within this systematic review should be acknowledged as we did not include grey literature. Additionally, language bias must be considered as we only included English-language publications. Conclusion Further development and testing of available questionnaire is warranted to ensure their robustness and validity in measuring risk perception of NCDs. All the identified factors deserve further exploration in longitudinal and experimental studies.


Introduction
According to the World Health Organization (WHO), non-communicable diseases (NCDs) are chronic diseases which tend to have long duration. The main types of NCD include cardiovascular diseases (CVDs), cancers, chronic respiratory diseases and diabetes (DM) [1]. NCDs kill 41 million every year, which is equivalent to 71% of worldwide deaths. The total annual number of NCD deaths is expected to increase to 55 million if the current trend continues [2]. Study also reported that NCDs impose a great impact on both households and impoverishment globally, at all levels of development [3]. Furthermore, the rising national health-care budget and the loss of productivity or ability to work due to NCDs pose serious and growing threats to many nations' economic stability [4].
In general, NCDs occur due to the combination of several factors, including genetic, physiological, environment and behavioural factors [1]. Behavioural factors such as harmful use of alcohol, physical inactivity, salt intake and tobacco use are modifiable [5]. An individual's behaviour is determined by many factors. According to the Theory of Planned Behaviour, behaviours are determined by behavioural intentions [6], while Social Leaning Theory posits that behaviour is determined by expectancies, incentives and self-efficacy [7]. Additionally, the Health Belief Model (HBM) hypothesizes that health-related behaviour depends on risk perception [7]. The term "risk perception" is defined as an individual's subjective judgement of the risk related to some event [8].
According to the HBM, there are four types of risk perception, including perceived susceptibility, perceived severity, perceived benefits and perceived barriers. Perceived susceptibility refers to the subjective risk of contracting a health condition, while perceived severity is the judgement on degree of seriousness of a given health condition. In addition, perceived benefits refers to an individual's estimate that a given behaviour will be effective in reducing the threat of disease, while perceived barrier refers to the barriers that must be overcome to follow the health recommendation [7,9]. An individual's perceived risk of developing a disease is an important factor towards adopting healthy lifestyles and the uptake of preventive health interventions [10].
Many studies have been conducted to assess the perceived risk of developing NCDs. The use of questionnaire as an instrument to measure an individual's risk perception of NCDs has been widely adopted [10,11]. The reason for such wide adoption is that the use of questionnaire is a feasible and inexpensive method for data collection. This method can also be used on a large number of respondents, enabling statistical analysis that give more significant power than other methods [11]. A robust questionnaire is essential in ensuring reliable and valid measurement of risk perception of NCDs. Hence, validity of questionnaire is an important consideration when choosing an instrument for assessing risk perception of NCDs.
To better understand risk perception of NCDs, identification of its associated factors is essential. Literatures have highlighted several factors associated with risk perception of certain perception of non-communicable diseases, and 5) described associated factors of risk perception of non-communicable diseases. We limited the publication date to 2012 and 2021 (articles published in the past 10 years) so that we can build our systematic review on the recent literature considering the dynamic pattern of risk perception [19,20]. Non-original articles such as conference proceedings, commentary, reports, review articles and systematic reviews were excluded.

Study selection
Two authors (JLMY and NA) screened the titles and abstracts independently based on the review questions. A total of 915 articles were removed during the screening. For the remaining 91 articles, 90 full-text were retrieved for assessment of eligibility, while the remaining one article was inaccessible due to post-publication correction [21]. Disagreements were resolved through discussion with a third researcher (ANA) to reach consensus. 4 articles were removed as two articles focused on accuracy of risk perception on breast cancer [22,23] and another two articles described the validation of questionnaire assessing awareness but not perception of breast cancer [24,25], leaving a total of 86 articles to proceed with quality appraisal.

Data extraction and synthesis
JLMY and NA extracted the data independently using a standardized data extraction form which is organized using Microsoft Excel. Information collected in the form include: (1) author, (2) publication year, (3) reference, (4) country, (5) study design, (6) statistical analysis and (7) results. Fig 1 shows the PRISMA flow diagram. Data synthesis was achieved using content analysis in order to condense text into fewer content-related categories [27].

Background of the eligible studies
A total of 86 studies were included in this systematic review (Tables 2 and 3). Slightly less than half of the studies (n = 40) were conducted in United States of America (USA). Other studies were conducted in Belgium, Brazil, Canada, China, Denmark, Finland, Germany, Ghana, Hong Kong, Iran, Iraq, Italy, Jordan, Kenya, Korea, Malaysia, Mexico, Myanmar, Netherland, Nigeria, South Africa, Spain, Sweden, Switzerland, Taiwan, Turkey and the United Kingdom (UK). A total of 45 articles were published between the year 2012 to 2016, while 41 articles were published between 2017 to 2021.
Majority of the included studies were quantitative studies (84 cross-sectional studies and one cohort study), while one study was of mixed methods design. Most of the studies (n = 72) explored the associated factors of risk perception of NCDs, while 11 studies described the questionnaire for assessing risk perception of NCDs. Three studies describe both the questionnaire used to assess risk perception of NCDs, as well as the associated factors of risk perception of NCDs. Table 2 shows the characteristics of the included studies related to questionnaire assessing risk perception of NCDs, including the measurement/s, study population, item development, analysis for validation and appraisal scoring. Table 3 shows the characteristics of the included studies related to associated factors of risk perception of NCDs, including the statistical analysis, associated factors, outcome (type of NCD) and quality appraisal scoring.

Associated factors of risk perception of NCDs
Most of the studies (n = 72) reported associations between personal factors with risk perception of NCDs, including hypertension, DM, CVDs, CKD, cancers, stroke, osteoporosis and  Table 3. Characteristics of studies related to factors associated with risk perception of NCDs (n = 75).       severe depression (Fig 2). A total of 24 studies reported associations between sociopsychological factors with risk perception of NCDs, while 16 studies reported associations between structural factors with risk perception of NCDs. Personal factors. Personal factors including demographic, lifestyle and health history factors [14] were found to be associated with risk perception of NCDs. The identified demographic factors were gender, age, ethnicity, religion, education level, income and marital status. 16 studies examined associations between gender and risk perception of NCDs. A total of 30 and 12 studies reported associations between age and ethnicity with risk perception of NCDs.

Structural Factors
Only one study each reported association between religion and marital status with NCD risk perception. A total of 11 studies reported associations between education level and NCD risk perception, while five studies found associations between income and risk perception of NCDs.
Several lifestyle factors were identified, including physical activity, smoking, alcohol consumption, sweet consumption, number of sexual partner and age at sexual debut. A total of five and ten studies reported associations between physical activity and smoking with NCD risk perception. Three and two studies reported associations between alcohol intake and sexual behaviour with NCD risk perception. Only one study reported association between sweets consumption and risk perception of DM.
The health history factors found to be associated with risk perception of NCDs include BMI, waist circumference, 2-hour glucose level, cholesterol level, blood pressure level, underlying NCD, underlying sexually transmitted disease, history of gestational DM, HIV status, use of oral pill/ injectable contraception, prior screening for NCD, family history of NCD and number of relative with NCD.
A total of 17 and two studies reported associations between BMI and waist circumference with NCD risk perception, respectively. Several studies (n = 14) reported associations between underlying comorbidities such as high blood pressure, high cholesterol, underlying NCDs, history of gestational DM, history of sexually transmitted disease and HIV positivity with risk perception of NCDs.
Only one study reported association between the use of hormonal contraception with risk perception of breast cancer. Three studies reported associations between prior screening of NCD with risk perception of NCD. A total of 31 studies reported associations between family history of NCD and/or number of relative with NCD with risk perception of NCDs.
Sociopsychological factors. Several sociopsychological factors were found to be associated with risk perception of NCDs, namely social exposure to NCD, perceived stigma by others, insured status, worry, distress, personal control, conscientiousness, emotional stability, optimistic bias, belief in the genetic cause of NCD, perceived oneself as overweight, believing overweight is a personal health problem, perceived risk of HPV exposure and perception of own health status. Only one study reported association between social exposure to NCD and perception of stigma by other with risk perception of NCDs, while three studies found association between insured status and risk perception of NCDs. Emotional status such as worry and distress have been associated with risk perception of NCDs in five and one study, respectively.
Only one study found that greater personal control was associated with higher DM risk perception. Personality traits such as conscientiousness, emotional stability and optimistic were also found to be associated with risk perception of NCDs in three studies. Previous studies (n = 2) have occasionally examined health beliefs, while 11 studies reported associations between perception regarding own health and risk perception of NCDs.
Structural factors. In addition to personal and sociopsychological factors that may influence NCD risk perception, structural factors were also identified. Under structural factors, several knowledge-related factors were identified, such as knowledge of NCD (n = 7), history of genetic counselling (n = 1), either discussed with or informed by healthcare professional about risk of NCD (n = 4), received recommendation for NCD screening by healthcare professional (n = 1) and discussion on NCD risk in the family (n = 1).

Critical appraisal of the included studies
The studies were appraised using the Mixed Methods Appraisal Tool (MMAT) [26]. The authors advised not to calculate overall score from the rating of each criterion using the latest version of MMAT (2018). However, due to problems faced by researchers in reporting the MMAT results, suggestion was provided for reporting of an overall score (5*****/100% quality criteria met; 4****/80% quality criteria met; 3***/60% quality criteria met; 2**/40% quality criteria met; 1*/20% quality criteria met). Of the included studies, 48 studies were given the score of 60%, while other 9, 25 and 4 studies were given the score of 100%, 80% and 40%, respectively. S2 File shows the scores of MMAT for each included study.

Discussion
An individual's risk perception of developing a disease is an important factor towards adopting healthy lifestyles and the uptake of preventive health interventions. To date, there has been no systematic review which has summarized the questionnaires assessing risk perception of NCDs and evaluated the evidence of factors influencing the risk perception of several major NCDs. Therefore, the purpose of this systematic review was to identify the best available evidence on questionnaire assessing risk perception of NCDs and factors associated with risk perception of NCDs. In this systematic review of 86 studies, we summarized the available questionnaire assessing risk perception of NCDs. We also identified several key personal, sociopsychological and structural factors associated with risk perception of NCDs.

Questionnaires measuring risk perception of NCDs
This review has identified questionnaires that explicitly assessed risk perception of NCDs or included at least five items assessing risk perception of NCDs. These questionnaires that assessed risk perception of NCDs pose very different questions, as they were developed based on different model, theory or adapted from different studies. Nevertheless, most of these questionnaires comprehensively measure various dimensions of risk perception of NCDs given the multi-dimensional nature of the concept.
For example, questionnaire developed by Mya et al included five domains of risk perception, namely perceived susceptibility, perceived benefit, perceived barrier, self-efficacy and behavioural change intention [31], while another questionnaire included 6 domains, namely perceived susceptibility, perceived severity, perceived benefit, perceived barriers, perceived cues to action and perceived self-efficacy [36]. Similarly, in other study assessing multidimensional construct such as empowerment in the cancer population, a questionnaire including several different but related dimensions of empowerment was used [110]. The multiple dimensions of the included questionnaires can contribute to simultaneous data collection on multiple dimensions of NCD risk perception with reduced bias.
The strength of the questionnaires included in this review is their comprehensiveness within a relatively short questionnaire. For example, the 48-item questionnaire by Agarwal et al can be completed within 20 minutes which is acceptable without overloading the respondents [34]. Additionally, the questionnaire by Anuar et al that explicitly assessed risk perception of NCD contains the most items (61) among all included questionnaires [33]. Nevertheless, the completion time of this questionnaire is expected to be much shorter compared with other comprehensive survey that require up to two hours [111]. With the short duration of administration, the included questionnaires seem applicable in various settings including clinical and research settings.
Regarding the validity, only a few of the included questionnaires tested construct validity using confirmatory factor analysis. The lack of construct validity assessment is also commonly seen in questionnaires assessing other constructs such as empowerment in cancer patients and parenting style [112,113]. Hence, more research is needed to understand whether the included questionnaires measure the NCD risk perception construct. In terms of mode of application, most of the included questionnaires used self-administered approach, which might improve their concurrent validity and reduce social desirability response bias as compared with interview approach [114]. Nevertheless, these questionnaires do not seem applicable in cross-country studies due to the validation in specific languages suitable for certain countries or region.

Associated factors of risk perception of NCDs
Demographic factors including gender, age, ethnicity, religion, education level, income and marital status play a role in risk perception of NCDs. Even though many studies reported that women were more likely to perceived themselves to be at risk of NCDs [45, 80,82], contradicting results have been reported [54,88]. Sulaiman et al postulated that the lower risk perception of DM among women may be due to optimism bias, which is a cognitive bias that cause them to believe that they are less likely to experience a negative event [54].
Ample evidence exists regarding the association between age and risk perception of NCDs. The higher risk perception of NCDs among those of older age is explainable, as NCDs are often associated with older age due to the higher prevalence of NCDs in the older age group [1,115]. Nevertheless, Kowall et al also suggested an explanation that older people perceive themselves to be at lower risk of NCDs due to their shorter life expectancy [67].
The association between ethnicity and risk perception of NCDs has been shown in the literature. The difference of risk perception between different ethnicities may be attributable to cultural salient factors such as wishful thinking, fatalistic beliefs and medical mistrust [61]. This finding highlights the need for further exploration of how cultural factors influence risk perception of NCDs. The higher risk perception of NCDs among people with higher educational attainment may be explained by the higher health literacy among people with higher educational attainment [116]. On the other hand, people with lower educational attainment may perceive themselves to be at risk of NCDs as they tend to be in the lower socioeconomic status group, which bears a disproportionate burden of NCDs [1].
The concerns of high socioeconomic status people about NCDs may be related to health literacy exposure, shaped by messages and media, as well as communication of health care professional [117]. However, those who had lower income may feel that they are more likely to be exposed to certain environmental hazards, which makes them feel vulnerable to cancer [85]. The higher risk perception of cervical cancer among married women may be due to the wellknown fact that married women had higher risk of HPV infection hence at increased risk of cervical cancer [118].
Lifestyle factors associated with risk perception of NCDs included physical activity, smoking, alcohol consumption, sweet consumption and sexual behaviour. The knowledge regarding the benefit of physical activity in preventing NCDs might lead to lower risk perception among those who are physically active [15]. However, higher level of physical activity was not found to predict lower NCD risk perception in a cohort study, which might be due to their weakness in measurement of physical activity whereby different items were used at baseline and follow-up [46].
The higher risk perception of NCDs among smokers might be expected, as the adverse health effects of smoking is well known, particularly risk of cancers, CVD and respiratory diseases [119][120][121]. Similarly, the increased risk perception of NCDs accompanying alcohol consumption may reflect an appropriate awareness of the risk of alcohol consumption. Additionally, the positive association between sweets consumption and risk perception of DM may be explainable as the fact that consumption of sugar-containing food can lead to DM is well known [122,123].
We also observed reported association between sexual behaviour and risk perception of NCDs. The higher risk perception of cervical cancer among those who had more sex partners is not surprising, as those who had more lifetime sexual partners and those practicing risky sexual lifestyle were more likely to be diagnosed with human papillomavirus infection which increases their risk of cervical cancer [64].
Health history factors associated with NCD risk perception included BMI, waist circumference, 2-hour glucose level, cholesterol level, blood pressure level, underlying NCD, underlying sexually transmitted disease, history of gestational DM, HIV status, use of oral pill/ injectable contraception, prior screening for NCD, family history of NCD and number of relative with NCD. The positive relationship between anthropometric values such as BMI and waist circumference with risk perception of NCD indicate that people seem to associate those readily visible factors with the risk of NCDs.
In addition to prior screening for NCD, underlying comorbidities such as high blood pressure, high cholesterol level, and pre-existing communicable and non-communicable diseases have also been associated with risk perception of NCDs. Those who had prior screening for NCD and underlying comorbidity may have more opportunity of receiving health counselling or advice from health care provider and therefore more likely to perceive risk for NCDs [83,101].
The higher risk perception of breast cancer among those using hormonal contraception is possibly due to the established fact that hormonal contraception increases the risk of breast cancer [124]. There is also ample evidence to support the relationship between family history of NCDs and risk perception of NCDs. For certain NCDs such as DM and cancers, family history is among the important risk factors, which reflects an individual's genetic predisposition for these NCDs [13,125]. Therefore, it was not surprising that those with family history of NCDs perceived higher risk of developing those NCDs.
Sociopsychological factors including social exposure to NCD, perceived stigma by others, insured status, worry, distress, personal control, conscientiousness, emotional stability, optimistic bias, belief in the genetic cause of NCD, perceived oneself as overweight, believing overweight is a personal health problem, perceived risk of HPV exposure and perception of own health status may also play a role in NCD risk perception. The association between social exposure to NCD and personality traits (conscientiousness, emotional stability, optimistic) with risk perception of NCD is well supported by the Health Belief Model which suggested that prior contact of certain disease and personality can influence an individual's risk perception of the disease [9].
The relationship between perception of stigmatized by other with risk perception of NCDs may be explained by the greater awareness of chronic disease among those who perceived stigma from others [84]. Studies also reported lower risk perception of NCDs among uninsured person, which may be a result of change in attitude as a form of self-protection. For example, those who are uninsured may feel that they cannot afford screening for cancer, causing them to push concerns about risk from their minds [71].
Emotional status such as worry and distress have been found to be associated with risk perception of NCDs. In view of these findings, future health interventions need to address NCDrelated worry and distress to motivate health-related behaviours. Greater personal control was associated with higher risk perception of DM. However, this finding is contrary to the findings by Kim et al, which may be attributed to differences in the nature and composition of study sample [126]. Based on this literature, health belief may be important in risk perception of NCDs. This finding is in agreement with the Health Belief Model which proposed that sociopsychological factors can influence risk perception of an individual [9].
Literature also consistently reported association between perception regarding own health with risk perception of NCDs. The greater risk perception of DM among those who perceived themselves as overweight is possibly due to the higher health literacy, making them understand and aware that being overweight increases their risk for DM [103]. The lower risk perception of NCDs among those who perceived good health status warrants further studies to investigate effective methods to communicate risk of NCDs among this group of individuals especially those who are at high risk of NCDs.
Structural factors associated with NCD risk perception included several knowledge-related factors, namely knowledge of NCD, history of genetic counselling, either discussed with or informed by healthcare professional about risk of NCD, received recommendation for NCD screening by healthcare professional and discussion on NCD risk in the family. In general, it is not surprising that, those who were more knowledgeable about certain NCD had high risk perception of NCD. Furthermore the Health Belief Model also identified knowledge as a factor that can influence risk perception towards certain disease [9].

Strengths and limitations
As with any research, this systematic review is not without limitations. Most of the included studies were of cross-sectional design, and therefore the quality of evidence was considered to be low and exhibit a high risk of bias. Another limitation relates to the measurement of risk perception of NCDs. Many studies assessed risk perception of NCDs using only a single item [46,58,82], which is insufficient to assess the multiple dimensions of the NCDs. Improving the measurement of risk perception of NCDs could help standardize the NCD risk perception literature.
The role of publication bias within this systematic review should be acknowledged as we did not include grey literature. We acknowledge the value of grey literature in systematic reviews. However, this systematic review did not include grey literature, in part due to the difficulty in searching and retrieving these documents, as well as time constraints. Another limitation is that we did not consult experts for source recommendations. Additionally, language bias must be considered as we only included English-language publications. Nevertheless, our search strategy has resulted in literature sourced from various countries where English is not the first language (China, Hong Kong, Italy, Spain). One of the strengths of this review is that we have included both questionnaires that explicitly assessed risk perception of NCDs, as well as questionnaires that included at least five items related to risk perception of NCDs. This process increased the chances of identifying items related to risk perception of NCDs for future research. Additionally, to the best of our knowledge, this is the first systematic review synthetizing research evidence on risk perception of several major NCDs, highlighting the available questionnaire assessing NCD risk perception and the correlates of perceived risk of acquiring NCDs.

Conclusion
This systematic review may serve as a guideline for researchers who intend to measure risk perception of NCDs, as the results provide an overview of the components included in those questionnaires, which can provide guidance in the choice of questionnaire. Nevertheless, further evidence is needed to support the validity of these questionnaires. In view of this limitation, researchers should pay attention in assessing validity in future questionnaire development work.
This systematic review also highlighted several key factors related to the risk perception of NCDs. All these key factors deserve further exploration in longitudinal and experimental studies. Based on the synthesized evidence, health interventions addressing risk perception of NCDs should not only focus on facts about personal factors (demographic, lifestyle and health history factors), but also on the sociopsychological and structural factors that may influence the risk perception of NCDs particularly among those at risk of NCDs.